The principle of data recovery

From Windows95, Windows system had a "recycle bin" used to story temporarily files that are deleted by the users. If the files are mistakenly deleted, we also can recover them from the "recycle bin". Even though, many users still prefer to deleted the file totally by pressing on "shift" button meanwhile rather than delete it to the recycle bin. Thus it can save the operation to delete the files completely and empty the recycle bin, and also can avoid the useless files that have been deleted to occupy the disk. But if so, that will lost the chance to recover the deleted files.

When we delete a file, in fact, it just modifies the first two bytes in the file header of this file. The modifying was mapped to the FAT (file allocation table) of the file system, and a deleted tag was added to the file, so that we can't see this file any more, but in fact, this file is not erased out of disk. And then, if there are some new files are written to the hard disk, they will cover the original position that the deleted files occupy.

That is to say, as long as and the space hasn't been covered by new files after the files are deleted, we still have chance to recover them. File recovery software is used to search and analyze the file header in the disk, and find out the files that have been marked and try to rewrite that two codes which were rewritten for the data recovery.

The principles of data recovery are nearly the same. The only difference is the ability in the file header scanning and recovering scattered file data.

However, to recover the files that are covered by the new data totally is nearly impossible. So if we want to successfully recover the mistakenly deleted files, we had better do the following points:

1. Try not to save the important files in the system partition. Usually the paging files in the system will be stored in the system partition. And the system operation will read them at any time. That is to say, whether we write new files or not, the deleted files will be covered by the written data of the system at any time.

2. When we find the files are mistakenly deleted, don't go on any operations which will make the data recovered, such as saving the file and copying the files and so on.

3. Use the file recovery software to scan and try to recover as soon as possible. You'd better store a kind of file recovery software to set aside to avoid the data damage when download or install software.

4. If we follow the above points, it will be promising to recover the deleted files completely. After recovery, certain verification is needed, because the recovered files may no longer complete, and the more we find the problem, the bigger hope to recover it will be.